docs: def Matsumoto_1974(mp, rhop, dp, rhog, D, Vterminal=1):
      r'''Calculates saltation velocity of the gas for pneumatic conveying,
      according to [1]_. Also described in [2]_.
  
      .. math::
          \mu = 0.448 \left(\frac{\rho_p}{\rho_f}\right)^{0.50}\left(\frac{Fr_p}
          {10}\right)^{-1.75}\left(\frac{Fr_s}{10}\right)^{3}
  
      .. math::
          Fr_s = \frac{V_{salt}}{\sqrt{gD}}
  
      .. math::
          Fr_p = \frac{V_{terminal}}{\sqrt{gd_p}}
  
      .. math::
          \mu = \frac{m_p}{\frac{\pi}{4}D^2V \rho_f}
  
      Parameters
      ----------
      mp : float
          Solid mass flow rate, [kg/s]
      rhop : float
          Particle density, [kg/m^3]
      dp : float
          Particle diameter, [m]
      rhog : float
          Gas density, [kg/m^3]
      D : float
          Diameter of pipe, [m]
      Vterminal : float
          Terminal velocity of particle settling in gas, [m/s]
  
      Returns
      -------
      V : float
          Saltation velocity of gas, [m/s]
  
      Notes
      -----
      Model is rearranged to be explicit in terms of saltation velocity
      internally.
      Result looks high, something may be wrong.
      For particles > 0.3 mm.
  
      Examples
      --------
      >>> Matsumoto_1974(mp=1., rhop=1000., dp=1E-3, rhog=1.2, D=0.1, Vterminal=5.24)
      19.583617317317895
  
      References
      ----------
      .. [1] Matsumoto, Shigeru, Michio Kara, Shozaburo Saito, and Siro Maeda.
         "Minimum Transport Velocity for Horizontal Pneumatic Conveying."
         Journal of Chemical Engineering of Japan 7, no. 6 (1974): 425-30.
         doi:10.1252/jcej.7.425.
      .. [2] Jones, Peter J., and L. S. Leung. "A Comparison of Correlations for
         Saltation Velocity in Horizontal Pneumatic Conveying." Industrial &
         Engineering Chemistry Process Design and Development 17, no. 4
         (October 1, 1978): 571-75. doi:10.1021/i260068a031
      '''
      A = pi/4*D**2
      Frp = Vterminal/(g*dp)**0.5
      Frs_sorta = 1./(g*D)**0.5
      expression1 = 0.448*(rhop/rhog)**0.5*(Frp/10.)**-1.75*(Frs_sorta/10.)**3
      expression2 = mp/rhog/A
      return (expression2/expression1)**(1/4.)